Barrier coatings

ABSTRACT

Composition comprising a polyblend of ethylene/vinyl chloride/acrylamide interpolymer and polyvinylidene-chloride useful as a flexible barrier coating for fibrous substrates.

United States Patent Ottinger et al. [4 1 June 20, 1972 [s41 BARRIERCOATINGS [56] References Cited [72] inventors: August F. Ottinger, St.Louis; Paul R. N D T E P Graham, Ballwin, both of Mo. U [TE S AT 5ATENTS 3,428,582 2/1969 Des Deex ..260/8 [73] 3,567,491 311971 Graham etal. ..1 17/76 [22] Filed: Feb. 26, 1971 Primary Evaminer-William H.Short [21 1 Appl' I Assistant Examiner-E. Nielsen Reh'gd U.$ A li u p.1Attorney-John E. Maurer et al. [63] Continuation-impart of Ser. No.718,367. April 3,

1968, Pat. No. 3,567,502. [57] ABSTRACT Composition comprising apolyblend of ethylene/vinyl [52] US. Cl. ..260/29.6 RW, 1 WI] 15 UA,ll7/l6l UT, chloride/acrylamide interpolymer and polyvinylidene- 260/897C chloride useful as a flexible barrier coating for fibrous sub- [51]Int.Cl ..C08I 29/22,C08f 37/18 sgr mg [58] FieldolSemh ..260/29.6RW,897C

9 Claims, No Drawings 1 BARRIER COATINGS This application is acontinuation in part of copending application Ser. No. 718,367 filedApr. 3, l968-now US. Pat. No. 3,567,502, which was issuedMarch 2, 1971.

This invention relates to a composition comprising a polyblend ofethylene/vinyl chloride/acrylamide interpolymer andpolyvinylidenechloride usefulas a flexible barrier coating for fibroussubstrates.

The term E/VCl/A interpolymer" as used herein means ethylene/vinylchloride/acrylamide terpolymers and high polymers thereof.

Fibrous substrates, such as paper, are widely used in packagingoperations. Paper, however, has very poor resistance to penetration bywater'vapor, gases, oil, solvents and greases. To improve resistance topenetration by such sub-' stances, paper has been coated with a varietyof materials. The most common paper coating is wax. While wax coatedpaper has good resistance to penetration while in a smooth or uncreasedcondition, it has poor resistance after it is'creased. Apparently thebrittleness of the wax is so greatthat creasing causes it to fractureand break thereby providing many areas through which 'water vapor canpass with little or no resistance. Additionally, wax coated paper doesnot serve to form a hard and scuff resistant surface.

The coating of paper with asphalt has also been tried and although goodresistance to water vapor is obtained, the coated paper has poorresistance after being creased. Additionally, asphalt is a black, toxicmaterial which limits its application as a paper coating; particularlyin the food packaging industry. Furthermore, asphalt coatings aresubject to changes in flow properties with a variance in temperature.

To improve water vapor, oil, solvent and grease resistance, paper hasbeen treated with polyvinylidene chloride. The characteristicbrittleness of polyvinylidene chloride causes failures of such coatingswith creasing. Attempts to improve this limited flexibility by the useof plasticizers and comonomers with the polyvinylidene chloride resultsin decreased resistance to penetration of water vapor. The poor impactresistance of the polyvinylidene chloride also results the rupture ofthefilm during high speed scoring and creasing.

' In view of the state of the art, it has become highly desirable to'discover materials which form flexible barrier coatings on fibroussubstrates having improved resistance to penetration by oil, grease,solvent and water vapor.

It is accordingly an object of this invention to provide a polyblendwhich will provide improved fibrous substrate coating compositions.

It is a further object of this invention to provide a polyblend havingimproved resistance to penetration by oil, grease, solvent and watervapor when used as a coating for fibrous substrates.

Other objects and advantages of the invention will be apparent to thoseskilled in the art from the following detailed description and claims.

The above and other objects of this invention are carried out by amethod which comprises admixing E/VCl/A interpolymer with'polyvinylidene chloride in order to form an E/VCl/Ainterpolymer-polyvinylidene chloride polyblend.

The polyblend compositions of this invention comprise from about 0.05 toabout 20 parts by weight of E/VCl/A interpolymer for each one part byweight of polyvinylidene chloride and preferably from about 0.l to about0.4 parts by weight of E/VCl/A interpolymer amide for each one part byweight of polyvinylidene chloride.

The compositions of this invention can be prepared by admixing theE/VCl/A interpolymer and the polyvinylidene chloride by any means knownin the art as for example by stirring, kneading or grinding. Suitablemixing equipment includes dough mixers, banberry mixers, rollers and thelike. Admixture can be carried out by dissolving each polymer in acommon solvent followed by solvent removal to obtain a homogeneouspolyblend. Suitable solvents include dimethylformamide,dimethylacetamide, pyridine and the like. Admixture can also be carriedout by adding the polyvinylidene chloride in dispersed form to anaqueous emulsion or dispersion of the E/VCl/A interpolymer. In manyapplications the E/VCl/A interpolymer-polyvinylidene chloride polyblendsin aqueous emulsion or dispersion will be used in latex form withoutfurther treatment. In the form of an aqueous dispersion or emulsion theE/VCl/A interpolymer polyvinylidene chloride polyblend can comprise fromabout 1 percent to about 99 percent by weight of the dispersion oremulsion and preferably from about 2 percent to 75 percent by weightwhen used as coating compositions.

The polyvinylidene chloride useful in this invention may be of anysuitable molecular weight (weight average molecular weight as measuredby gel permeation chromatography), but generally the molecular weight isnot less than about 25,000 and may be as high as 500,000 or more.Preferably the weight average molecular weight is from about 100,000 toabout 200,000.

The E/VCl/A interpolymers which are useful in the preparation of theE/VCl/A interpolymer-polyvinylidene chloride compositions of thisinvention generally contain from about 2 to about 70 weight percentethylene, from about 30 to about 88 weight percent vinyl chloride, andfrom about 0.1 to about 10 weight percent of an additional polar monomercomponent. The polar monomer component can be entirely acrylamide or aportion of the acrylamide can be replaced by one or more polar monomersselected from the group consisting of acrylonitrile, N-(lower alkyl)acrylamide and N-(lower alkyl) methacrylamide containing from one tothree carbon atoms in the lower alkyl groups, N-methylol acrylamide,N[2- (2-methyl-4-oxopentyl)] acrylamide, acrylic acid, methacrylic acid,and alkali metal and ammonium salts of acrylic and methacry-acrylicacids, maleic acid, fumaric acid, half and complete alkali metal andammonium salts of maleic and fumaric acid, aconitic acid, itaconic acid,citra conic acid, and alkali metal and ammonium salts thereof, acrylyland methacrylyl esters of hydroxyalkanoic acids having from two to aboutsix carbon atoms in the alkanoic acid moieties, acrylylamides andmethacrylylamides of aminoalkanoic acids having from two to about sixcarbons in the aminoalkanoic acid, hydroxyethyl and hydroxypropyl estersof acrylic, methacrylic, maleic, and fumaric acids, vinyl esters ofalkanoic acids having from one to six carbon atoms such as vinylacetate, vinyl propionate, and lower alkyl (one to six carbon atoms)sulfonic acid, vinyl esters of phenylsulfonic acids, andalkylphenylsulfonic acids and acrylyl and methacrylyl esters ofhydroxyalkylsulfonic acids having from one to six carbon atoms in saidalkyl moieties, and hydroxyalkylsulfonamides having from one to sixcarbon atoms in said hydroxyalkyl moieties. The polar monomer componentgenerally contains at least 10 weight percent acrylamide and preferablyat least 50 percent acrylamide.

Thus the interpolymers are at least terpolymers containing ethylene,vinyl chloride and acrylamide and may be a quaternary or higher polymerscontaining one or more of the above exemplified additional polarmonomers in small quantities,

Generally such additional polar monomers will not be present in theinterpolymer inquantities greater than about 3 percent by weight.

It is preferred that the interpolymer contain from about 15 percent toabout 70 percent ethylene, 30 percent to about percent vinyl chloride,and from about 1 percent to about 5 percent acrylamide. A specificexample of choice is a terpolymer containing from about 19 to about 23percent ethylene, about 74 to about 78 percent vinyl chloride, and fromabout 2 to about 4 percent acrylamide.

The interpolymers used in accordance with this invention can bemodified, but non-modified interpolymers are preferred. Theinterpolymers are particularly amenable to hydrolytic modification bythe use of small quantities of a strongly alkaline material such as analkali metal hydroxide, or a quaternary ammonium hydroxide such astetramethyl ammonium hydroxide, or by a strong acid such as the mineralacids, e.g., hydrochloric, sulfuric, phosphoric, nitric. The base oracid used preferably has an ionization constant higher than at 25 C.

The hydrolytic modification is carried out by treating an aqueousdispersion or polymer latex of the ethylene, vinyl chloride, andacrylamide with aqueous base or acid in an amount chemically equivalentto from about 0.1 percent to about 100 percent of the amide equivalentin the interpolymer.

Specific examples of additional polar monomers which can be used, asdescribed above, to replace part of the acrylamide in the polar monomercomponent of the interpolymer useful in this invention includeacrylonitrile, N-methacrylamide, N- ethylacrylamide, N-propylacrylamide,N-metholylacrylamide, methacrylamide, acrylic, methacrylic, maleic,fumaric, itaconic, aconitic, and citraconic acids and alkali metal andammonium salts of such acids, preferably the sodium potassium orammonium salts, alkyl esters of such acids, e. g., methyl acrylate,ethyl acrylate, butyl acrylate, methyl methacrylate, butyl methacrylate,ethyl methacrylate, mono ethyl maleate, dipropyl fumarate, acrylyl3-hydroxypr0pionate, methacrylyl hexamide Z-hydroxyethyl and2-hydroxypropyl esters of acrylic, methacrylic, maleic, fumaric,itaconic, aconitic and citraconic acids, vinyl formate, vinyl acetate,vinyl hexanoate, vinyl and alkyl esters of propanesulfonic acid, vinylphenylsulfonate, acrylyl and methacrylyl esters of 2-hydroxypropylsulfonic acid, and N-acrylyl and N-methacrylyl 2 hydroxypropanamides.

Illustrative of interpolymers which are useful in this invention areethylene/vinyl chloride/acrylamide, ethylene/vinylchloride/acrylamide/hydroxyethylacrylate, ethylene/vinylchloride/acrylamide/N-isopropylacrylamide, ethylene/vinlychloride/acrylamide/diammonium itaconate, ethylene/vinylchloride/acrylamide monobutyl acid maleate, ethylene/vinylchloride/acrylamide/N-methacrylyl propionamide, ethylene/vinylchloride/acrylamide/sodium acrylate and ethylene/vinylchloride/acrylamide/sodium methacrylate.

The ElVCl/A interpolymers generally have a molecular weight (weightaverage molecular weight) from about 20,000 to about 150,000 as measuredby intrinsic viscosity or gel permeation chromotography.

The E/VCl/A interpolymers useful in this invention are readily preparedby various means well known to the art. The interpolymers can beprepared by first mixing ethylene and vinyl chloride in an aqueousmedium in the presence of any suitable anionic or nonionic emulsifierand any initiator capable of generating free radicals'in the chemicalmixture at the chosen reaction temperature and pressure. The acrylamide,preferably in aqueous solution either alone or mixed with theappropriate amounts of other polar monomers, is added to thepolymerizing ethylene and vinyl chloride mixture gradually throughoutthe reaction. The addition of the acrylamide is preferably begun afterabout 40 to 50 percent of the desired conversion of the ethylene andvinyl chloride has been reached. A shell-core latex in which the polarmonomer is concentrated in the outer layers is produced.

The ethylene/vinyl chloride interpolymers used in this invention arepreferably prepared by a process which comprises mixing ethylene andvinyl chloride monomers in the presence of an alkaline bufferedreduction-oxidation (redox) initiatorcatalyst system, water, and fromabout 1 percent to about 8 percent by weight based upon the monomerfeed, or from about 4 percent to about 7 percent based upon the polymerproduct of an anionic or nonionic emulsifying agent having ahydrophilic-lipophilic balance (HLB) value of from about 10 to about 40,and reacting the mixture at a temperature and pressure and for a timesufficient to cause polymerization between the ethylene and vinylchloride, and then to introduce acrylamide, either alone, or mixed withother monomers in minor amounts in an appropriate diluent such as waterinto the pressurized polymerizing reaction mixture of the ethylene andvinyl chloride. This process is described in detail in U. 8. Pat. No3,428,582 and the subject matter thereof is expressly incorporatedherein by reference.

The following examples will illustrate this invention. Parts and percentare by weight unless otherwise indicated. In the polymer preparationexamples, all of the polymerization are carried out in a 3,820 ml.pressure vessel at 30 C. at a rotary stirrer speed of 600 rpm.

EXAMPLE 1 This example illustrates the preparation of a 21/76/3ethylene/vinyl chloride/acrylamide trpolymer latex, and thepost-stabilization of such latex with an emulsifier.

Reaction Vessel Initial Charge:

.0 g K S O (KPS) l5.0 g NaHCO 0.8 g Fe(NO;,) 911,0 1.5 g Tetrasodiumethylenediaminetetraacetate (Na EDTA) 1.2 g Sodium lauryl sulfate (SLS)H 0 to make 1700 ml 450 g Vinyl chloride (VCl) 150 g Ethylene (E) andthe pressure was kept constant by the addition of pure vinyl chloride asrequired. After three hours had elapsed, a 50 percent solution ofacrylamide in water solution was added at 40 ml/hr. The reaction stoppedafter 5.5 hours and the feed streams were turned off. A total of 1330 gof VCl,'95 ml of the 50 percent acrylamide, 27 ml of the l M SFS/LS M NH,OH solution, and 92 ml of the 25 percent SLS solution had been added.The resulting polymer latex was vented out the bottom of the autoclave.A total of about 3,500 g of the ethylene/vinyl chloride/acrylamidepolymer latex was obtained containing 47 percent total solids, and 1.5percent sodium lauryl sulfate (based on the weight of the polymer). Ithad a pH of 7.7. The composition of the terpolymer was about 21/76/3ethylene/vinyl chloride/acrylamide. After addition of 1.5 percent ofsodium dodecyl benzene sulfonate or 3 percent tridecyloxy(CH CH O), H,the latex was ready for use directly as a barrier coating.

EXAMPLE 2 This example illustrates the preparation of the basemodifiedethylene/vinyl chloride/acrylamide terpolymer.

Using the same reaction Vessel and ingredients as are described inExample l, except that only 10.0 g of KPS, and only 0.5 g of SLS wasused in the initial ingredient charge. The SFS/Nl-LOH solution was addedat the rate of 4 ml/hr and the SL8 solution was added at 8 ml/hr. Thepolymerization reaction stopped after 5.75 hours with a total of about1,340 g of vinyl chloride, ml of acrylamide solution, 23 ml ofSFS/Nl-LOH solution, and 43 ml of 25 percent SLS being added. Theresultant terpolymer latex was post-stabilized by mixing therewith anadditional 17 ml of 25 percent sodium lauryl sulfate (SLS). Thestabilized latex was then vented from the bottom of the reaction vessel.There was obtained 3,460 g of material containing 49 percent totalsolids, 1 percent of the SL8 and essentially the same tel-polymer asdescribed in Example The particle size of this polymer latex wassomewhat larger than that of Example 1.

This stabilized ethylene/vinyl chloride/acrylamide terpolymer latex waswarmed at 50 C. for 4 to 16 hours after adding 0.42.0 g of sodiumhydroxide (added thereto as a l0 percent NaOH in water solution) perkilogram of latex.

' EXAMPLE 3 A four monomer component polymer latex was prepared asfollows:

A pressure reaction vessel was initially charged with 9.0 g KPS 12.0 gNaHCO 1.5 g Na EDTA 0.5 g SLS H O to make 1,700 ml 470 g VCl Thismixture was sealed and warmed to 1,550 psig. Polymerization was startedby pumping into the vessel contents a l M SLS/1.5 M Nl-LOH solution atthe rate of 4 ml/hr. At the same time 10 ml/hr of a 25 percent SLS wasadded. Vinyl chloride sufficient to keep the pressure constant was addedthroughout the reaction. At the end of 3 hours of polymerization anaqueous solution containing 40 percent acryiamide and 10 percent sodiumacrylate was added to the reactor atthe rate of 24 ml/hr. After 6 hours,the reaction stopped and a total of 591 g of vinyl chloride, 52 ml of 25percent SLS, 27 ml of SFS/Nl-LOH and 72 ml of the acrylamide/acrylatesolution had been added. Unreacted ethylene and vinyl chloride werevented from the top of the reactor to lower the pressure to about 250psig, and then the latex was taken out through the bottom of thereactor. There was thus obtained about 3,060 g of latex containing 43percent solids, and 1.1 percent sodium lauryl sulfate. The polymercomposition was a 21/76/2.3/0.7 ethylene/vinylchloride/acrylamide/sodium acrylate polymer. It was suitable for usedirectly as a coating composition for paper and paperboard. Theprocedure is repeated substituting for the sodium acrylate an equivalentamount of sodium methacrylate. An ethylene/vinylchloridel-acrylamidelsodium methacrylate of substantially the samemonomer proportions is obtained.

lnterpolymers prepared in a manner analogous to the procedure describedin Example 1 are shown in Table 1.

The interpolymers prepared in Examples 4 through 6 are modified withsodium hydroxide to obtain hydrolyzedpolymer latices having thefollowing solids content:

Latex Example N0. Polymer Example No. of Table l Solids EXAMPLES 12-] 7Following the procedure of Example 3 and equivalent amount of thecomponent tabulated below is substituted for the sodium acrylate toobtain a latex polymer described below composed of substantially thesame proportions as the product of Example 3.

l2 Component= Hvdroxvethvl acrvlate Polymer =Ethylenelvmylchlorrde/acrylamrde hydroxyethylacrylate l3 Component=N-isopropylacrylamide Polymer Ethylene/vinyl chloride/acrylamide/N-isupropylacrylamide l4 ComponenF N-ethylmethacrylamide PolymerEthylene/vinyl chloride/acrylamide/ N-ethylmethlmethacrylamide l5Component= A diammonium salt of itaconnic acid Ethylene/vinylchloride/acrylamide/ Polymer diammonrum itaconate Component= Monobutylacid maleate Polymer Ethylene/vinyl chloride/acrylamide/ monobutyl acidmaleate l7 Component= N-methacrylylpropionamide Ethylene/vinylchloride/accylamide/ N-methacrylylpropionamide EXAMPLE 18 An aqueousdispersion of ethylene/vinyl chloride/ acrylamide (21/76/3) interpolymerprepared substantially in accordance with'Example l and containing about45 weight percent polymer solids is coagulated by means oftetrahydrofuran. The interpolymer is washed with water and dried. About100 parts of polyvinylidene chloride having a weight average molecularweight of about 100,000 is admixed with about 150 parts of the dryinterpolymer by kneading to form a polyblend composition. The polyblendcomposition can be used as is or dissolved in a solvent or dispersed inaqueous media.

EXAMPLE 19 An aqueous dispersion of E/VCl/A interpolymer containingabout 45 percent polymer solids is admixed with aqueous dispersions ofpolyvinylidene chloride containing about 25 percent polymer solids usingmoderate stirring over a period of one-fourth hour. The polyvinylidenechloride has a molecularweight of about 100,000. The E/VCl/Ainterpolymer contains 21 percent ethylene, 76 percent vinyl chloride and3 percent acrylamide. The water is removed by evaporation and thepolyblend compositions are observed for compatibility, i.e., exudation,blooming or tack development. Results and further details are given inTable ll below wherein the amount of E/VCl/A interpolymer in thepolyblend compositions is expressed in parts by weight per l00 parts byweight of polyvinylidene chloride.

Polymer TABLE II E/VCl/A interpolymer, Amount Compatibility l Good 10Excellent 22 Excellent 50 Excellent Good The fibrous substrates to whichthe polyblend compositions are applied include papers of all types, suchas bond writing paper, fibrous paperboards such as cardboard, chipboard,carton stock, and the like, wrapping papers or boards, or liners forcontainers intended for the packaging of foods, greases, chewing gum;soap, soap powders, cosmetics, calking compounds, etc. The coated papersmay also be used as wallpapers, papers for lining drawers and shelves,especially in linen closets, kitchen cabinets and the like, and thecoated paper or paperboards may be used as bookcovers or book pages.

The polyblends may be applied to building construction papers andboards, such as the facing paper on plasterboard. It may be used as arelease-coating on a paper to be used as a liner in a concrete moldingform or adapted to be used for covering freshly-laid concrete roads.

The fibrous substrate, such as paper, which may be coated with latexpolyblends of polyvinylidene chloride polymer latex and ethylene/vinylchloride/acrylamide interpolymer latex to produce a product of enhancedbarrier characteristics may contain from about 0.5 to pounds of latexblend on one side per ream. (A ream is 3,000 sq. ft. and equals 500sheets, 24 inches by 36 inches.) Generally, however, about 1 to 20pounds of latex blend per ream is adequate while 1 to 4 pounds is allthat is needed for many purposes.

The processes for applying a latex polyblend coating to fibroussubstrates are well known in the art. Such techniques include spraying,roller coating, air-knife coating, trailing blade coating, curtaincoater and use of a Mayer rod (machine).

The following examples illustrate the advantageous and unexpectedproperties which areachieved by the used the polyblends of the presentinvention as fibrous substrate coating materials, but it is not intendedthat this invention be limited by or to the examples.

The latex polyblend are applied to the felt side of the substrate bymeans of a wire wound rod. Coating rod numbers 6, 18 and 28-are utilizedin applying the film. A No. 6 rod has a smaller wire diameter and morewinds for a given rod length which deposits a light continuous wet filmwhereas the N0. 28 rod has a larger wire diameter and fewer winds perinch which deposits at much heavier film.

A series of paper sheets were coated with latex blends as shown in Table111 containing varying proportions of polyvinylidene chloride polymerand E/VCl/A interpolymers. in these examples all parts are parts byweight. The coatings are then tested for various physical properties.The test procedures are hereinafter described and the results are listedin Tables 1V and V.

The test methods used to determine the physical properties of thefibrous substrates coated with the latex polyblends of this inventionare listed below along with explanatory notes where necessary. Sampleswere conditioned according to TAPPI T402m-49 before testing. The paperbase stock used in the testing hereinafter described is indicated whereapplicable for individual examples.

Oil ResistanceCreased Box Test A 6 X 6 inch coated one side specimenblank is folded diagonally from comer to corner, each fold is subjectedto a 5 lb. pressure. The blank is further folded one'inch from each edgeand then made up into a 4 X 4 inch box having 1 inch side walls with thecoated surface inside. All creases, except those made by the side wallfolds converge as an apex in the center of the box bottom. 50 cc NO. 10SAE oil is poured into the box and the time required to penetrate thecreased areas is noted.

Moisture-Vapor Transmission Rate A.S.T.M.' 3-988 (tropicalatmosphere)-Reported as Grams H O/100 sq. inches/24 hrs. at 100 F. and90 percent relative humidity.

TABLE IIL-IROPERTIES 0F POLYVINYLIDENE CHLO- RIDE POLYMER, ETHYLENEVINYL CHLORIDE ACRYLAMIDE INTERPOLYMER LATEX POLYBLENDS Component LatexExan1plo Percent Viscosity. total cps. at

Composition PVDO u 1 2 S solids 25 C. p11

The Polyblends of Table 111 were used in preparing a series of coatedpapers of 30 lb blue white glassine stock by applying two coats of eachcomposition to one side of each sheet with a No. 6 rod. The water vaportransmission rates of the coated papers are set forth in Table IV.

TABLE IV Moisture Vapor Transmission Rates for Coatings of Latex The oilresistance properties obtained with a series of paper stock of 50 1bbleached kraft, double coated with a No. 6 rod on one side of each sheetwith the compositions of Table 111 are shown in Table V.

POLYVINYLIDENE CHLORIDE POLYMER AND ETI'IYLENE/VINYL CHLORIDE/ACRYLAMIDE IN'IE RPOLYMERS Number of penetrations Coating wt.,Time, U nct'cascd Cast film Composition 1b./1,000 11:. seconds Greasedareas characteristic 4. 74 660 13 32. 5 4. 42 330 14 14 Flexible. 4. 03390 10. 5 22. 5 Do. 4. 23 270 9 32. 5 D0. 4. 18 135 8 45 Do. 4. 90 112.6 7 37. 5 Do. 4. 78 210 18 D0. 4. 55 185 15 100 D0. 5. 11 10 100 Do. 4.83 117 8 75 Do. 4. 45 92 i) 50 Do. 3. 87 480 13 20 D0. 3. 79 540 9. 5 20D0. 4. 05 1, 095 4. 5 6 D0. 4. 28 1, 695 0 3 D0. 4. 7) 6, 540 0 5 D0.

The results set forth in Tables IV and V show that compositions Bthrough P impart to the paper the desirable combination of oil and watervapor resistance and good flexibility. Such combination of properties isnot attainable when polyvinylidene chloride polymer is used as the solecoating material.

The replacement of latices l, 2 and 8 of the compositions B through Pwith Examples 3 through 7 and 9 through 17 results in coated papershaving properties similar to those presented in Tables lV'and V.Paperboard such as cardboard, carton stock and chipboard exhibit similarexcellent properties as shown in Tables IV and V when coated with thelatex polyblends of this invention.

The paper to be coated can be of a wide variety of types includingkraft, bond, parchment, etc. The type, weight and other physicalproperties of the'paper to which the coating is applied do notsignificantly offer the improvement in oil resistance and moisture vaportransmission rate brought about by the method of the invention.

The coated papers provided by the present invention have utility formany purposes which will be obvious to those skilled in the art. Inparticular, the coated papers may be used to wrap food products where itis desired to prevent the transmission of moisture from the atmosphereto the packaged product. The coated papers are easily heat sealed andhold liquids well. As a result, such coated papers can be used in themanufacture of paper drinking cups and the like.

The E/VCl/A interpolymer-polyvinylidene chloride polyblend compositionsof this invention are also useful as protective coatings for substratessuch as wood, metal and glass; as laminating adhesives for safety glass,paper products and the like; as wrapping films and sheeting and asshaped articles such as protective bumper extensions and caps. When usedas protective coatings for substrates such as wood, metal and glass thepolyblend compositions can be applied in the form of an organic solventsolution or in the form of aqueous dispersions optionally containingpigments and dyes.

The embodiments of this invention in which a particular property orprivilege is claimed are defined as follows:

i. Ethylene-vinyl chloride-acrylamide interpolymerpolyvinylidenechloride polyblend composition comprising (I) an ethylene-vinylchloride-acrylamide interpolymer selected from the group consisting of(A) an ethylene-vinyl chlorideacrylamide interpolymer containing fromabout 2 to about 70 weight percent ethylene, from about 30 to about 88weight percent vinyl chloride, and from 0.1 to about weight percent ofan additional polar component selected from the group consisting of 1.acrylamide, and

2. acrylamide in combination with at least one additional polar monomerselected from the group consisting of acrylonitrile, N-(alkyl)acrylamide having from one to three carbon atoms in said alkyl groups,N-methylol acrylamide, N[2-( 2-methyl-4-oxopentyl)] acrylamide,methacrylamide, N-(alkyl) methacrylamide having from can onto threecarbon atoms in said alkyl groups, acrylic acid, methacrylic acid andalkali metal and ammonium salts of acrylic and methacrylic acid, maleicand fumaric acids, itaconic and citraconic acids, half alkyl esters ofmaleic, fumaric, itaconic, and citraconic acids having from one to sixcarbon atoms in said alkyl groups, acrylyland methacrylyl esters ofhydroxyalkanoic acids having from two to six carbon atoms in saidalkanoic acids, acrylylamide and methacrylylamides of aminoalkanoicacids having from two to six carbon atoms in said aminoalkano- I icacid, hydroxyethyl and hydroxypropyl esters of acrylic, methacrylic,maleic and fumaric acids, vinyl esters of alkanoic acids having from oneto six carbon atoms, vinyl esters of alkylsulfonic acids having from oneto six carbon atoms in the alkyl group, vinyl esters of phenylsulfonicacids, acrylyl and methacrylyl esters of hydroxyalkylsulfonic acidhaving from one to six carbon atoms in said alkyl moieties, and acrylyland methacrylyl ester of hydroxyalkylsuflonamides, having from 1 to 6carbon atoms in said hydroxyalkyl moieties; and (B) interpolymers of thetype described in (A) treated with an acid or a base having anionization constant higher than about l0 in amounts equivalent to up toabout 100 percent of the amide content of said interpolymer, and (II)polyvinylidene chloride wherein (l) is present in an amount from about0.05 parts to about 20 parts for each one part by weight of (II). 2.Composition of claim 1 wherein the interpolymer contains from about 15to about 70 weight percent ethylene, from about 30 to about weightpercent vinyl chloride and from about I to about 5 weight percentacrylamide.

3. Composition of claim 1 wherein the interpolymer is represented by(B).

4. Composition of claim 1 wherein the ethylene-vinyl chloride-acrylamideinterpolymer is present in an amount from about 0.1 parts to about 0.4parts by weight for each one part by weight of (ll).

5. Composition of claim 1 wherein the interpolymer contains from about15 to about 70 weight percent ethylene, from about 30 toabout 85 weightpercent vinyl chloride and from about I to about 5 weight percentacrylamide and is present in an amount from about 0.! parts to about 0.4parts by weight for each one part by weight of ll).

6. Composition of claim 1 wherein the interpolymer contains about 76percent vinyl chloride, about 21 percent ethylene and about 3 percentacrylamide.

7. Composition of claim 1 wherein the additional polar componentcomprises acrylamide and N-methylol acrylamide.

8. Composition comprising a dispersion of the polyblend composition ofclaim 1 in an aqueous medium.

9. Composition of claim 8 wherein the polyblend composition theinterpolymer contains from about 15 to about 70 weight percent ethylene,from about 30 to about 85 weight percent vinyl chloride and from about 1to about 5 weight percent acrylamide.

2. Composition of claim 1 wherein the interpolymer contains from about15 to about 70 weight percent ethylene, from about 30 to about 85 weightpercent vinyl chloride and from about 1 to about 5 weight percentacrylamide.
 2. acrylamide in combination with at least one additionalpolar monomer selected from the group consisting of acrylonitrile,N-(alkyl) acrylamide having from one to three carbon atoms in said alkylgroups, N-methylol acrylamide, N(2-(2-methyl-4-oxopentyl)) acrylamide,methacrylamide, N-(alkyl) methacrylamide having from one to three carbonatoms in said alkyl groups, acrylic acid, methacrylic acid and alkalimetal and ammonium salts of acrylic and methacrylic acid, maleic andfumaric acids, itaconic and citraconic acids, half alkyl esters ofmaleic, fumaric, itaconic, and citraconic acids having from one to sixcarbon atoms in said alkyl groups, acrylyl and methacrylyl esters ofhydroxyalkanoic acids having from two to six carbon atoms in saidalkanoic acids, acrylylamide and methacrylylamides of aminoalkanoicacids having from two to six carbon atoms in said aminoalkanoic acid,hydroxyethyl and hydroxypropyl esters of acrylic, methacrylic, maleicand fumaric acids, vinyl esters of alkanoic acids having from one to sixcarbon atoms, vinyl esters of alkylsulfonic acids having from one to sixcarbon atoms in the alkyl group, vinyl esters of phenylsulfonic acids,acrylyl and methacrylyl esters of hydroxyalkylsulfonic acid having fromone to six carbon atoms in said alkyl moieties, and acrylyl andmethacrylyl ester of hydroxyalkylsuflonamides, having from 1 to 6 carbonatoms in said hydroxyalkyl moieties; and (B) interpolymers of the typedescribed in (A) treated with an acid or a base having an ionizationconstant higher than about 10 4 in amounts equivalent to up to about 100percent of the amide content of said interpolymer, and (II)polyvinylidene chloride wherein (I) is present in an amount from about0.05 parts to about 20 parts for each one part by weight of (II). 3.Composition of claim 1 wherein the interpolymer is represented by (B).4. Composition of claim 1 wherein the ethylene-vinyl chloride-acrylamideinterpolymer is present in an amount from about 0.1 parts to about 0.4parts by weight for each one part by weight of (II).
 5. Composition ofclaim 1 wherein the interpolymer contains from about 15 to about 70weight percent ethylene, from about 30 to about 85 weight percent vinylchloride and from about 1 to about 5 weight percent acrylamide and ispresent in an amount from about 0.1 parts to about 0.4 parts by weightfor each one part by weight of (II).
 6. Composition of claim 1 whereinthe interpolymer contains about 76 percent vinyl chloride, about 21percent ethylene and abOut 3 percent acrylamide.
 7. Composition of claim1 wherein the additional polar component comprises acrylamide andN-methylol acrylamide.
 8. Composition comprising a dispersion of thepolyblend composition of claim 1 in an aqueous medium.
 9. Composition ofclaim 8 wherein the polyblend composition the interpolymer contains fromabout 15 to about 70 weight percent ethylene, from about 30 to about 85weight percent vinyl chloride and from about 1 to about 5 weight percentacrylamide.